Shock-resistant silicon steel hardened with titanium



Patented Oct. 8, 1946 ENED WITH TITANIUM i Linwood M. Brown, Homestead,Pa.

No Drawing. Application October 19, 1942,

Serial No. 462,508

c Claims. 1 (01. 75-123) 1 My invention relates to steel alloys, andparticularly, though not exclusively, to steel alloy used in makingpercussion tools.

The object of the invention is to provide a steel alloy in which highresistance to fatigue and crystallization is obtained in conjunctionwith increased tensile strength, hardness, and toughness.

Another object is to provide a self-hardening, the characteristics menPer cent Carbon 0.40 to 1.00 Manganese 0.35 to 2.50 Silicon 0.80 to 2.75Molybdenum 0.15 to 2.90 Titanium 0.10 to 0.90 Iron Remainder Thecombined molybdenum and titanium ranges substantially from 0.25% to3.80%. The phosphorus and sulphur impurities are held to normal values.I

The steel alloy will preferably be produced in an electric furnace, andit will be understood that traces of other usual elements may be presentin the product, depending upon the composition of the melts that werepreviously made in the melting furnace. For example, immediately priorto making a batch of my steel, the steel producer may have been usingthe furnace for the production of stainless steel, or high chromiumsteel, in which case-the lining of the furnace may be contaminated withchromium, or nickel, or copper, or tungsten, or other alloys orcombinations, and if the furnace is not thoroughly washed out by themelting of one or more heats of plain carbon steels, certain inclusions,not desired, but permissible, will be found in my steel. In a typicalcase a heat of my steel picked up chromium in the amount of from 0.06%to 0.07%, W i e this chromium was not desired, it was permissible. Thesame may be said of other alloys that will ordinarily be picked up inthe melting furnace.

The carbon, manganese, and silicon will be added to the mix in thefurnace, and the molybdenum and titanium additions preferably, althoughnot necessarily, will be made in the ladle,

in which case the temperature of the mix in the ladle Will be increasedapproximately two hundred degrees above normal pouring temperature.

Ordinarily, ferro-compounds of silicon, manganese, molybdenum, andtitanium are best to use in the mix.

In the manufacture of titanium steels hitherto, substantial quantitiesofthe added titanium have been lost, ordinarily as much as 25%. (See page21 of the book entitled:Titanium and Its Use in Steel,-copyrighted inthe year 19 10 by The Titanium AlloyManufacturing Company of NiagaraFalls, New York. 1 See also page 951 of The Making-Shaping and Treatingof Steel, Fifth edition, by The Carnegie-Illinois Steel Corporation,published in Pittsburgh, Pennsylvania, 1940.) I have discovered that if,the silicon content of the molten bath of metal is maintained greaterthan, and preferably from one and one quarter to three or more times asgreat as, the titanium content,-

the titanium will not be lost, but will substantially all persist as analloying component of the finished steel.

It has been known in the art that both titanium and silicon may be usedas deoxidizers in the production of steel, but so far as I am aware, noone has heretofore realized that, in the case of a titanium steel,particularly a titanium steel containing molybdenum, silicon may be usedas an effective agent to prevent the loss of any substantial portion ofthe titanium introduced to the mix.

It is believed that in the improved steel alloy of my composition amolybdenum-titanium carbide is formed, this being indicated by the factthat from 12% to 1 1% of the carbon originally added to the melt isabsorbed. The steel is of fine grain structure, great density andtoughness, and exceedingly high tensile strength.

Titanium when present in steel, particularly in amounts above 0.10%,is'known as an inhibitor of the hardenability of the steel, and it isremarkable that the titanium steel of my invention possesses high self-hardening qualities. When forged and cooled in the atmosphere, thesteel develops a hardness of from C to 62 C, Rockwell. The steel mayalso be heat treated, by raising it to a temperature of 1600 F. andcooling it in water or in oil, and it may be used with or withouttempering, depending upon the particular service. The steel possesseshigh red-hardness. It has high resistance to fatigue and crystallizationand will not fail under shock, and (by virtue of its high red-hardness)it is enduring under conditions of service in which heat is generated by3. friction and abrasion. Possessing such qualities as these my steel isexcellent for use in cutter bits of mining machinery, pneumatic chiselsfor chipping and cutting hot or cold metal, cold cutters, heading dies,forging dies, bushings for pneumatic hammers, shear blades for hot orcold Work, rivet bull dies for either pneumatic or. hydraulic machines,battering mauls: and sledges; andihollow and solid drills. And it Willbe und'erstoodthat many other fields lie open to the use of such steel.

The application for these Letters Patent consisted in a continuationinpart; of application Serial No. 407,439, filed by me on August.1'9; 1941", for Titanium steel and method of production.

Many variations in the proportionsofthe alloying elements may be madewithout: lenarting from the invention, as defined in the appendedclaims.

I claim as my invention:

1. A shock-enduring steel alloy of high hardenabilityhavingsubstanti'ally the composition: carbon, DAG-1.00%; manganese,0.35-2.50 silicon, 0.80-2.75%; molybdenum, ;1'5'-2;90.% titanium,0.10-0.90%'; the silicon being in excess of the titanium, and theremainder substantially iron.

2. A shock-enduring: steel alloy of high hardenability havingsubstantially the composition: carbon, GAO-1.00% manganese, 0 .35 2 .50g silicon, 0.80-2.7 molybdenum, (HS-2.90%; titanium, GAO-0.90%; thesili'con being i excess of the titanium, and theeremaindersubstantiallyiron, the titanium content of the steel alloy comprising almost all-ofthetitanium introduced to themix.

3; A shock enduring steel alloyof high hardenability containing, inaddition to its essential ferrous content, carbon, manganese, silicon.

4 I molybdenum, and titanium as the principal alloying ingredients, thecombined molybdenum and titanium content ranging substantially from0.25% to 3.80% and including at least 0.10% titanium and 0.15%molybdenum, and the silicon being in excess of the titanium.

I 4. A shock-enduring steel alloy of high hardenability cpntaimng, in.addition to; its essential ferrous content, carbon, manganese, silicon.molybdenum, and titanium as the only alloying ingredients, the combinedmodybdenum and titanium content. ranging substantially from 0.25% to3.80% and including at least 0.15% molybdenum and 0.10% titanium, thesilicon ranging between 0.80 and 2.75%.

A shock-enduring steel alloy of high hardenability containing, inaddition to its essential ferrous content, carbon, silicon, molybdenum,and titanium as the only alloying ingredients, the combined molybdenumand titanium content ranging substantially from 0.25% to 3.80% andincluding at least 0.10% titanium and t least 0.15% molybdenum, the:silicon content beingv at leastone and onequarter times the titaniumcontent.

6. A. shock-enduring. steel alloy of high hardena'bility containing, inaddition. to its essential ferrous content, carbon, silicon, molybdenumand titanium, these being the only: alloying ingredients, the combinedmolybdenum: and titanium content ranging substantially from 0.25 to3.80%. and: including at least. 0.10% titanium and at l'east.0.1.5%molybdenum, and the silicon content being at least one and one-quartertimes the titanium content, the titanium content of the steel. alloycomprising almost all of the: titanium introduced to the mix. v

LINWOOD M. BROWN.

